Electric discharge tube of the cavity resonator type



Feb. 2, 1954 F. COETERIER Filed? Aug. 24. 1950 INVENTOR FREDERIK COETERRIER AGENT Patented Feb. 2, 1954 assets? *ELECTRTU DIS'GHARGE TUBE OFTHE- UAVI'IY' RESUNATORL TYPE Frederik--Cocterier, -Eindhoven,;Netherla1id ;signorto JHartford National Bank" and-Trust Company, Hartford, Conn, as trustee AppIictitiom-Adgu'stfif 1950,;SeriarN 05181.139

-- Claims priority, application- Netherlands September '9, 1949 3 Claims. 1

Th'e'present invention "relates to an electric discharge tube of "the type comprising'a'resonant cavity'which is excited around acircular'path-by an electron beam'producedby an annular cath- I 'ode.

With known devices of the aforementioned kind the energy produced is conducted to the outside ofthe tube with the use of a coupling loop, which'loop merges into a concentric conductor. A disadvantage inherent in the use of such coupling loops in these tubes which opcrate with comparatively high energies, is that the coupling loop readily burns through; also the coupling provided by the loop with the resonant 1 cavity in these known structures not 1 Sufiicintly' tight.

It is accordingly an objectv of this invention to provide a new and improved discharge tube particularly adaptable for-highenergy outputs.

It is a further object of this invention to 'provide a new and improved tube having a superior power output coupling arrangement.

Other objects and advantageswill become apparent from "the specification taken in connection with the accompanying drawing wherein the invention is embodied in definite form.

According to the invention, with an electric discharge tube comprising a resonant cavity which is excited along a circular path by an electron beam produced by an annular cathode the energy produced is conducted away with the use of a system of concentric conductors which, internally of the resonant cavity, merge into two parallel plates provided with apertures to allow the passage of the electron beam. This ensures a very tight coupling between the concentric outlet conductors and the oscillatory system and enables high energies to be conducted away through this outlet system.

In order that the invention may be more clearly understood and readily carried into effect, it will now be described in detail with reference to the accompanying drawing, in which Fig. 1 is an elevational sectional view of the electrode system of a tube according to the invention, and

Fig. 2 is a plan view in section taken on line 11-11 of Fig. 1.

Referring now to the drawing in detail there is shown in Fig. 1 an evacuated discharge tube having an enclosing envelope l. Mounted at the upper end of the envelope is a system of reflecting electrodes 2 and 3. At the lower end of the envelope is an annular cathode 4. Positioned adjacent the cathode 4 are beam elecelectrodes 5, 6 and "the a flat cylinder.

ed by :metallic cavity 7 is also provided, internally io--with circular coupling plates) and H.

plates l0 and II have v is a concentric conductor trodes*5- and '6. interposed between -the-'-beam I reflecting electrodes-2 and' 3, isa resonant'cavity, '1, in the *form of The- "upper-and lower walls of cavity l are each "provided with apertures 8 and -8 respectively, in the shape of segments tr a circle. The various segments 8 or8' are shuntstraps 9; The resonant thereof, "The circularly shaped apertures l2 and I3 respectively. Theseapertures I2 and-l3 ofthe coupling plates are shunted'by strips I4. Extending from the cavityTand preferably concentric with the annular cathode'l system having an outer condutor l5 and'an inner conductor 16. 'Outer conductor [5 isan extension of circular plate l0 and is connected tothe lower wall oflcavity 1 While inner conductor 6' is an extensionof a circular plate H. An insulating block I! and a metal block I 8 having the same diameter as the outer conductor I 5, are provided to insure of proper spacing of the various components.

"' Reflector electrode 3 has apertures l9, shunted by strips 20.

In the operation of the tube, electrons emanated by the annular cathode 4 are accelerated by a potential applied to the electrode system and directed by the beam electrodes 5 and 6 through the aperture 8' in the lower wall of the resonant cavity 1, and then consecutively through the apertures 13 and I2 and 8 to the reflecting electrodes 2 and 3 where they are reflected back through the apertures in the reverse order, in the manner well known to the art. The plates l0 and II together with the resonant cavity 7 constitute the oscillatory system for the device shown. The high frequency energy is coupled out of the cavity 1, by the concentric conductor system In, H.

The electrode system 1, l0, II gets a potential of some hundreds of volts positive with respect to the cathode. Reflecting electrode 3 gets about cathode potential and reflecting electrode 2 a negative potential. Between cathode 4 and electrode 2 a more or less parabolic field is set up in which the electrons oscillate with constant frequency. Electrons that have lost their energy are deflected to the electrodes and caught by them. The sealing of the tube is explained more fully in Philips Technical Review 8, 257-266, 1946.

While the invention is particularly adaptable .for tubes of the velocity modulation type and there has been described herein a tube of the reflex klystron type and a structure that is considered a preferred embodiment of the invention it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention.

What I claim is:

1. An electric discharge tube comprising an annular cathode for the generation of an electron beam, an electrode in said tube and spaced from said cathode, a cavity resonator interposed between said cathode and said electrode, said cavity resonator having apertures therein for the pas sage of said electron beam, two substantially parallel coupling plates in said cavity resonator arranged with their planes transverse to the path of the said electron beam and each having apertures therein for the passage of said electron beam, and a concentric conductor output system extending out of said cavity resonator, and through said annular cathode at substantially right angles to said parallel plates said concentric conductor system having an inner conductor merged with one of said parallel lates and an outer conductor merged with the other of said parallel plates.

2. An electric discharge tube comprising an annular cathode for the generation of an electron beam, an electrode in said tube and spaced.

from said cathode, a cylindrical oscillatory system interposed between said cathode and said electrode and including a cavity resonator and two substantially parallel coupling plates in said cavity resonator arranged with their planes trans,

verse to the path of the said electron beam and axially aligned with said annular cathode, said oscillatory system having apertures therethrough for the passage of said electron beam, and a concentric conductor system extending out of said 4 cavity resonator and through the center of said annular cathode at substantially right angles to said parallel plates, said system having an inner conductor merged with one of said parallel plates and an outer conductor merged with the other of said parallel plates.

3. An electric discharge tube comprising an annular cathode, for the generation of an electron beam, a reflecting electrode in said tube and spaced from said cathode, a substantially flat cylindrical cavity resonator interposed between said cathode and said reflecting electrode and aligned therewith, said cavity resonator having apertures therein for the passage of said electron beam, two substantially parallel plates in said cavity resonator arranged with their planes transverse to the path of the said electron beam and each having apertures therein for the pas- ,sage of said electron beam, and a concentric conductor output system extending out or said cavity resonator through the center of said annular cathode at substantially right angles to said parallel plates, said system having an inner conductor merged to the parallel plate remote from said cathode and an outer conductor merged with the parallel plate adjacent said cathode.

' FREDERIK COETERIER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 23115138 Gocdchild Nov. 26, 1946 2,414,517 Fremlin Jan. 21, 1947 2,458,009 Ingram June 4, 1949 2,466,063 Varian Apr. 5, 1949 2,527,600 Touraton et al Oct. 31, 1950 OTHER REFERENCES Article by F. Coeterier, pp. 68-69, Tele-Tech of May 1947. 

